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#include <algorithm>
#include <cstdio>
#include <utility>
#include <vector>
using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define FORD(i,a,b) for(int i=(b)-1;i>=(a);--i)
#define REP(i,n) FOR(i,0,n)
#define REPD(i,n) FORD(i,0,n)
#define VAR(v,w) __typeof(w) v=(w)
#define FORE(it,c) for(VAR(it,(c).begin());it!=(c).end();++it)
#define PB push_back
#define ALL(c) (c).begin(),(c).end()
#define MP make_pair
#define FT first
#define SD second
#define INT(x) int x; scanf("%d", &x)

typedef pair<int,int> PII;
typedef vector<PII> VII;

int end(const PII& x) {
	return (x.FT << 1) / x.SD;
}

bool comp(const PII& x, const PII& y) {
	return end(x) > end(y);
}

int main() {
	INT(t);
	REP(tt,t) {
		INT(n);
		scanf("\n");
		VII v;
		bool f = 1;
		int x = 0;
		REP(i,n) {
			if (getchar() == '1') {
				if (x) v.PB(MP(x, 2 - f));
				x = 0;
				f = 0;
			} else ++x;
		}
		if (f) {
			printf("0\n");
			continue;
		}
		if (x) v.PB(MP(x, 1));
		sort(ALL(v), comp);
		int d = 0, r = n;
		FORE(it,v) {
			int l = it->FT - d * it->SD;
			if (l <= 0) continue;
			if (it->SD == 2 && l >= 2) {
				++r;
				if (l > 2) ++d;
			}
			r -= l;
			++d;
		}
		printf("%d\n", r);
	}
}